Thornsbury Bailey Brown (May 15, 1829 – May 22, 1861) of Taylor County, Virginia (now West Virginia) is generally considered the first Union soldier killed by a Confederate soldier during the American Civil War. Brown, a member of a Virginia militia or volunteer company which supported the Union with the grade of private, was killed by a member of a Virginia militia or volunteer company which supported the Confederacy at Fetterman, Virginia (now West Virginia) on May 22, 1861. The members of both companies were from the same general vicinity of Taylor County.